Of course its understandable that you would get frustrated but it takes your strength as a player to stay calm and collected.

You can't expect your teammates to win lane any more than you can guarantee you win your own. And yes, it's totally true that people don't like to accept blame for themselves (A.k.a always blame the jungler).

Yelling at them won't make them play any better and for all we know, they may be a great player with a rough start that needs to keep his mood up to make plays later.

My reccomendation...
If they die a few times, it just happens. Sometimes people get countered, or they are having an off day, or whatever. But if they die like 5+ times in laning, try and see what they are doing wrong. If they aren't warding, they are playing to aggresive or they are doing something else, try and give them tips.

What alot of players don't seem to understand is "noob feeder uninstall plz" is not going to make them play any better.

Yes it is understandable to be frustrated if someone loses a lane and feeds somewhat.
However If someone loses their lane they know it.
They know they lost it, everyone in the games knows they lost it.
What do you get from pointing it out to them?
If they haven't done anything to provoke you and you start flaming them for losing their lane ofcourse they're going to get defensive. You''d be pointing out an obvious fact that serves no benefit to the team or anyone you'd just be putting them down for your own benefit. This is why people get defensive and start throwing out excuses.

Why do you feel the need to point out the obvious to the player? They know they lost their lane everyone in the game knows it. Nothing productive will come out of you pointing out the obvious to them. Of course someone will get defensive and throw around excuses. Did you think about helping them in their lane if it was constantly pushed? The jungler isn't the only one who can go and help a lane that is constantly pushed to a tower.

Yes it can be frustrating if someone lost their lane. But it can also be very frustrating when someone feels the need to point out this and this player lost their lane when they know it. Instead of wasting time pointing out the obvious give them tips or help them out.